A
Boolean expression is a notation that you can use to tell a search engine
more about what you do and do not want included in your search. These
expressions are named after the famous Irish mathematician George
Boole. In Anglicans Online search, you can use the terms and and or and not,
and you can use parentheses. If you have a little bit of experience with
Boolean expressions you will need to pay attention to our not operator,
because it is not a unary not, which is customary. Our not operator
is binary, and has the meaning "but without".

The
most common mistake in people's understanding of Boolean expressions
is that the use of and causes you to find fewer pages, and the
use of or causes you to find more pages. You might think that
asking for "font and narthex" would give you the pages
containing the word "font" and the pages containing the word "narthex",
but in truth it gives you the pages that contain both the word "font" and
the word "narthex".

Here
are some Boolean expressions, what they mean, and what they do.

church
and catholic

Find
pages that contain both the words "church" and "catholic".

font
or fount

Find
pages that contain either the word "font" or the word "fount"

church
and (catholic or anglican or episcopal)

Find
pages that contain the word church, and that also contain either
the word "catholic" or the word "anglican" or
the word "episcopal".

crozier
not flying

Find
pages that contain the word "crozier" but do not contain
the word "flying"

narthex
and (font or fount)

Find
pages that contain the word "narthex" and also contain
either the word "font" or "fount".

(bishop
or archbishop) and (diocese or archdiocese)

Find
pages that contain either the word "bishop" or "archbishop",
and that also contain the word "diocese" or "archdiocese"